This is an interview, in it’s entirety that Doug Lockhart did for the PROTech Boards, just about two years or so ago. It has not appeared to the best of our knowledge outside of the two primary sites, HVACPROTech.com and HVACPROTech.org until now. We are planning a follow up interview with Doug, to talk about his impressions relevant to the progress the digital manifold gauges has seen in those two years, it’s progress, it’s potential and we’ll talk about the two new models currently scheduled for release in the next several weeks and touch on some of the technology under development for future DGRSA generational changes.
I want to personally thank Doug for taking the time from his busy schedule to answer these questions. As well as sending the images of the generational steps that the DRSA has already made.
(1). Doug, can you talk to us a little about your experience in the field – and what requirements the Canadian government mandates in order to practice in this trade.
In the province of British Columbia the refrigeration trade is a ‘compulsory trade’ as I believe it is in all provinces in Canada. This means that a tech needs to either be an indentured apprentice or a TQ’d journeyman. (TQ means Trade Qualified which is the successful completion of a 4-5 year apprenticeship of 6-8 weeks/year of training with successful period end exams culminating with the TQ exam.) If the mark achieved in the final exam is above 70% then the ‘red seal’ or inter-provincial status is also given allowing the tech to now work in any province in the country.
(2).What led to the inspiration for the original BTD, the forerunner to the DRSA right?
I was frustrated with how I would be expected to pay a top price for a vehicle tech to service my van but when I then went on the roof of that same dealership I was expected to work for basically 1/3 of the price. I felt that since I was basically using the same tools that my old partner was using in 1946 except that the gauge dials had 12, 22 and 502 on them instead of S02 and Methyl Chloride!! I figured we in the trade needed to suit up and show up in more modern gear if we wanted to be paid in modern wages! I had a Fluke digital multi-meter since 1984 and we still had nothing digital in the refrigeration manifold arena.
(3). I realize I’m asking for a twenty year plus biography here, but can you walk us through the development process involved with the DRSA. I mean from conception, to prototype to final product. Some of the pitfalls, some early design issues and the ultimate triumphs when they were over come.
Almost twenty years ago when I first embarked on this journey I found out that the parts and components needed to build the DRSA (Digital Refrigeration System Analyzer) were going to cost me over $3500.00! The pressure transducers were effectively $1400 each and the rest of the components would also be expensive. The proliferation of ABS brakes in the late 80s and early 90s are what facilitated the first build. It was a relative low accuracy un-amplified Ametek transducer that was at the heart of the First DRSA and the electronics were basic with the famous patented bargraph becoming the early recognizable signature to the Digi-Cool product. We needed a faceplate which was hand built for the first prototypes with the aid of hand rubbed Letrafilm and Letraset . My background in Radio Control Modeling helped here with case and faceplate design/build. Since we had no internet and basically no computers yet I had to do all my sourcing of product by the Thomas Register at the local library and over the phone garnering many monthly $800.00 phone bills. It was still late 80s and the fax was just becoming available at one of my customers, so this is the arduous manner in which I gathered information. Early samples from suppliers were hard to come by and expensive. The second prototype heralded a custom LCD display and an actual silk-screened overlay. Switches for the keys were built out of cork, metal foil tape and finger etchings on a PCB daughter-board. I was achieving all this whilst running an HVAC/R business in a 10-12 hour work day and then spending until 2-3 am working on the DRSAs. Brenda, my tireless wife supported me all the way with many, many long nights trying to ready another prototype for a prospective partner right along side me. The software early on was algorithm based to minimize the need for expensive memory for all the refrigerants. Since I had only 12, 22, 500, 502 and Ammonia on board it wasn’t yet that heavy loaded in terms of memory headroom. When Greg came on board we then seen the development of the BTD1000 and then consequently the DRSA1100. Since the superheat and subcooling were confusing I felt it better to leave it off the first BTD1000 as the techs acceptance of the technology would be difficult enough with just the digital box itself. I was dead wrong as the Robinair product (who incidentally was talking to us on an OEM basis prior to releasing their product) had the superheat and subcooling and thus now the techs demanded it. Ritchie’s interest in our product predicated the 1200 and it’s ‘straight bolt on’ to the Ritchie Titan manifold. The next exciting product we produce will have……..stay tuned!
(4). Without disclosing proprietary technology can you talk about what – specifically makes the DRSA tick – thermistors, transducers or other technologies that the field tech may be a little less than familiar with – and what guided your decision to include the specific technology as it would be compared to other generally accepted methods of pressure and temperature indication.
Pressure transducers are the main means by which we convert the analogue pressure signal into an analogue voltage signal. We utilize a relatively accurate A to D converter for both the pressure transducers and temperature thermistor for the superheat and subcooling measurements. The microprocessor is a masked micro with enough headroom for the many refrigerants plus the EEPROM chip that will allow us to add up to 50 more refrigerants. The custom designed LCD gives all the information on it without having to drill down through layers of menus. With all the distractions of cell phones, two way radios, customers, etc I think the plain wide view information is crucial to preventing misinformation and mistakes because we used the previous service call’s refrigerant by mistake!! The multiplexed LCD allows for power optimization and long battery life.
(5). Doug, without playing the name game or specific brand comparisons, we talked on the phone about some of the design characteristics of the DRSA, like the engineered in temperature compensation of the case to allow for wide ambient swings without adversely affecting the performance of the instrument, along those same lines of thought, I wonder if you could differentiate for us other design considerations that set the DRSA heads and shoulders above both the recent as well as early applications of digital technology to gauge sets.
The real show stopper with our DRSA is the bargraph coupled with the selectable numeric update. It was tremendously time consuming and expensive to get the sampling/discard/averaging ratios right to eliminate noise but not lose the accuracy or real time events taking place in the system. Since it is updated visually/digitally every ¼ of a second you get a very accurate accounting of real time system pressure dynamics. You can for instance watch an R507 freezer pulldown on all the other competitors’ units travel from 48..47..46..45.. psig and for all intents and purposes be happy with the compressor’s/system’s performance. With Digi-Cool’s unit if you see the bargraph between 47 and 46 psig jump up 2 psi, (8 lowside bargraph divisions) this would indicate the flashing of liquid back through the suction line!!!! Not a symptom you would want to ignore if you are to warranty the compressor and keep the customer and your reputation! This is unique to Digi-Cool only and we feel absolutely crucial to a DRSA that would be used every day in the modern HVAC/R world.
Durability along with accuracy is very important so the case on our units are virtually water tight with all case entry points tightly gasketed or o-ringed. The battery is vented by a gore-tex to prevent build up of explosive gases (hydrogen) produced as a battery discharges but also prevent water ingress. The LCD pocket is built with mechanical spacers and bolted in place to prevent shifting. The sizing is designed to prevent crushing of the LCD in -25degF two meter drop tests. The case is built of engineered plastic that withstand these two meter (6 foot high) drop tests from -25 degC up to 85 degC with NO damage or breakage. The case was personally tested with a 16 oz claw hammer to not break until the 3rd blow as hard as a fat cranky old 6’2” 230# can hit the case on solid concrete. We have tested the case with all common POE, mineral, AB and vacuum oils for 96 hours with no etching of crazing. The same was done with the overlays and we then tested both the overlays and cases with muriatic acid as well as HF acid oil from a burnout reclaim drum and had again no etching of crazing of the overlay or case. We also have added UV stabilizers to the case and overlays to prevent long term damage to the product important to rooftop techs.
(6). In a recent thread at the Forums a member pointed out an apparent association or partnership between Digi-Cool and Ritchie Yellow Jacket. Can you briefly describe the nature of that relationship and what if any affect it would have on the technician as the end user of the DRSA.
We very early on approached Ritchie with a prototype and Steve Ritchie was very gracious but felt we might be ahead of the market in terms of acceptance. Our predecessors left the industry with some trepidations on DRSAs and very hesitant to try again. When we were in the marketplace for just a little over two years I again met Steve Ritchie at AHR in Orlando and he agreed that the product had proven itself in superior suitability to application as well as durability which were the two issues he was very concerned about. Ritchie had evaluated a great number of competitive products and we were extremely flattered that they chose Digi-Cool. The Digi-Cool DRSA and the Ritchie 500736 are functionally the same so affect to the end user will not be anything other than positive feedback and insight that a highly respected and professional company like Ritchie can bring to the table.
(7). It was recently noted that the original BTD model was being discontinued from the DRSA family. Were there any specific issues or concerns that led to the decision to remove it from the available options to the technician?
We had an enviable sub 1% failure rate with the BTD1000 but with the 13 SEER issues and TEV proliferation in these units a device without superheat and subcooling capability was simply viewed as not a valuable product. One of the three tenets of Digi-Cool is ‘responsive’ to the needs of our industry. This is why we continually find the contact and feedback from my own industry techs so important to keeping Digi-Cool going in the right direction in terms of needs and wants in present and future products. Digi-Cool prides itself in being totally accessible to it’s end users and collaboration on how they feel the product is presently used and needs to evolve we feel, is essential to the survival of the company. Building a better stethoscope for a roofer is not gonna help his trade!!!
( 8 ). For those that may not be familiar with the DRSA and its generational evolutions from the BTD to the 1100 to the newly introduced 1200 can you walk us through both the technological differences in the generational progression as well as the real world differences, in other words what differences would the technician that may be accustomed to using the BTD immediately note if he were to switch to the 1100 or the 1200.
As mentioned previously the BTD1000 was built without superheat or subcooling as we felt that this was not a concept that would be well accepted being that the Digital gauge manifold was not a universally accepted tool to be needed in the trade. I felt that further complicating the transition from analogue to digital with confusing features was not a direction that was needed. We had some focus groups on this issue and acceptance was going to be difficult to surmount even without a learning curve. The DRSA1100 was an incorporation of the BTD1000 plus the superheat and subcooling features. All the durability of the BTD1000 was kept with the waterproof temperature sensor. We kept the 4-AA batteries and complete ‘brick outhouse’ tough design but again maintained the horizontal learning curve priding ourselves on the fact that 95% of the techs never have had to pick up the quick start card nor the manual. The device is very intuitive. We are very proud of this fact…….very important to this male….never, I repeat never, let anyone, especially your spouse, catch you reading the directions!!!
(9). Assuming the answers you have provided regarding the DRSA as an instrument - the technology and research and development involved in getting the instrument into the hands of the technician don’t adequately answer the question for everyone. How would you address cost objections to the product?
No self respecting tech minds paying for quality if that indeed is what he will receive. That being said we at Digi-Cool are on the constant hunt for better value in products. The problem is that the 100+ parts count in the BOM (bill of materials) are not of the same magnitude as the sub dollar parts count in the MP3 players of today save the display and memory. We do see a day when we can get a sub $400 and maybe $300 relatively full featured DRSA. The main obstacle to this is the Catch 22 of the electronics industry coupled with the fact that our market doesn’t facilitate the huge markdowns you see when ordering 100,000 quantities that the consumer electronics trade is used to. That Catch 22 of not being able to get the price down ‘cause we can’t get the quantity up and since we can’t get the quantity up ‘cause we can’t get the price down is the eternal elusive problem in the electronics industry. Since our industry is relatively small compared to the automotive, electric or plumbing industry we have a formidable challenge ahead of us. When it’s too hard for all others; it’s just right for us!
(10). Based on discussions we have had as well as recent threads posted at the Forums by you – the indication would be that there are several advanced features that are being considered for future incorporation into the existing DRSA technology, can you go into detail regarding these potential upgrades and perhaps a tentative timeline in their incorporation and release.
I don’t want to give away all the iterations planned but we in this industry have a way too many heavy items to pack up onto a roof! Garth Denison once said “when you give the toughest job to the laziest guy (me) then he will come up some of the most ingenious inventions to take care of those tasks”. Coming from 30+ years in the trade climbing those ladders and crawling into those crawlspaces and dragging in hundreds of pounds of tools, we need to incorporate more of the day to day tools into the DRSA. I am very interested to see where the two issues of data logging and wireless will go. Since information overload is prevalent everywhere these days the proper collection and dissemination of data logging downloading will be very important. As for the wireless, what happens when we are up on a roof with a wireless diagnostic device and the landlord of the building has decided to improve his/her bottom line by installing the local cellular providers transceivers up on the this same roof? What happens at a sensitive government facilty? at a hospital where we can’t now use our cellular phones? Will we need to have both capabilities in the same devices? This is the reason why I wanted to get other tech’s viewpoints on this. I know myself that I burn the hell out of wires and hoses now so more hoses and wires will be worse. What does the status quo want and what will they suffer in price up-charges to achieve this full wireless?
Again I know what I want but what does the industry want.?????
(11). As a continuation of the above question, are there any additional products on the horizon for Digi-Cool, I mean aside from DRSA changes is there anything, that you can discuss that may be in development that will carry the Digi-Cool branding?
I see a day when we’ll have to print out proof of charging of refrigerant on site as well as proof of system integrity with vacuum maintenance. Inherent meters and system information with real time graphing and plotting on a Mollier chart are exciting indeed. If we could say positively that the 5 ton A/C or H/P compressor was turning out only 4 ton of cooling then we would convert ALL of our tentative recommendations into highly profitable sales. To this point we have an amperage and some pressures that say the compressor SHOULD be doing 4.85 ton….but what is it really doing????? I have always felt ethically uneasy with condemning a system based on theory rather than nailing down the problem with real measured values. At this point we have NO MEANS to check a refrigeration system’s capacity accurately, in my opinion. The present means are using one part removed secondary parameters measured against theoretical curves! We need actual flow rates, pressures, subcooling, NREs, mass flows etc…then and only then will we have real time actual numbers…..No problems; only opportunities!
(12). The final question I’m going to give you Doug, should appeal to your entrepreneurial side. What in your vision is the ultimate DRSA going to look like. What are its capabilities going to be – and how much of what you see for the DRSA is achievable from a practical standpoint? And what is not?
Coming from again the tech side I NEVER want to get rid of the human touch. I’ve seen a ton of computer diagnostic devices that give information and supposedly troubleshoot the job but how useful or accurate are they. We never can replace (at least not in my lifetime) the incredible mind’s ability to adapt. That ability of the human mind to aqueous to all combinations and permutations of the present constantly changing situations is the real beauty and value in the human factor.
We also cannot allow ourselves to get to the point of letting our tools run us but rather have our tools work for us and make our lives easier. We have seen a real change in philosophy over the last decade or two. The proliferation of computer/information devices whereby we are inundated with this information and the need to update software and dedicate HUGE amounts of time to learning curves along with these re-learning curves associated with upgrades is overwhelming us. We now are effectively working for our tools instead of them for us! We need to be careful not to let this happen in our industry but that is my job as a manufacturer to only release REAL user friendly upgrades with zero learning curves that immediately improve bottom life and/or quality of life as well. Cool stuff….hang on for the ride!
From the very first handcrafted prototype through the DRSA 1200 Signature Series. For the first time anywhere on the internet, the 20 year evolution of the DRSA in pictures.
Also remember a pdf formatted copy of this interview as well as the images is available soon in the Technical Archives at http://www.hvacprotech.org
